Automatically resetting deiverter for pneumatic conveyers



D. E. SCHAETZEL ET AL 2,649,339 AUTOMATICALLY RESETTING DIVERTER FOR PNEUMATIC CONVEYERS Aug. 18, 1953 Filed June 28, 1960 2 Sheets-Sheet l INVENTOR DONALD E. SCHAETZEL RANDALL J. CHILDRESS A TTORNE Y 8" 13, 1953 D. E. SCHAETZEL ET AL 2,649,339

AUTOMATICALLY RESETTING DIVERTER FOR PNEUMATIC CONVEYERS Filed June 28, 1950 2 Sheets-Sheet 2 INVENTOR DONALD E. SCHAETZEL RANDALL J. CHILDRESS BY W ATTORNEY Patented Aug. 18, 1953 AUTOMATICALLY RESETTING DIVERTER FOR PNEUMATIC CONVEYERS Donald E. Schaetzel, Minneapolis, Minn., and Randall J. Childress, Norwalk, Calif., assignors to General Mills, Inc., a corporation of Delaware Application June 28, 1950, Serial No. 17 0,892

16 Claims.

The present application relates to pneumatic conveyers and more particularly to an improved automatic device for diversion of stock from such a conveyer upon decrease of the rate of air flow below a predetermined minimum. One form of automatic diverter for such a purpose is shown in the prior copending application of Randall J. Childress, Serial No. 163,554, filed May 22, 1950, and assigned to the same assignee as the present invention.

The present invention is particularly directed to an improved form of diverter plate which is capable of precise adjustment for automatic restoration to normal operating position whenever the volume rate of air flow in the conveyer system exceeds a predetermined minimum. Thus the present device is designed to perform two functions. The first function is the automatic diversion of the stock away from the pneumatic conveyer intake whenever the volume rate of air flow decreases below the predetermined minimum, for example as a result of a partially choked condition in the conveyer system, vor as a result of some failure in the air moving means itself. The second function is the automatic restoration of the normal operating condition as described above as soon as the volume rate of flow again exceeds the specified minimum.

One object of the present invention is the provision of an automatic diverter for pneumatic systems capable of performing the above functions.

Another object of the invention is the provision of a diverter for pneumatic systems in which precise adjustment can be obtained to balance the various forces acting on the diverter at a predetermined point.

Another object is the provision of a diverter which is freely rotatable on a horizontal axis, the location of which can be adjusted laterally to vary the effective location of the center of impact of the stock against the diverter plate.

A further object is the provision of a diverter, which after restoration from dumping to operating position will be self-cleaning by reason of air flowing through an auxiliary intake and across the upper area of the diverter.

Still another object is the provision of an automatic diverter having an airfoil-like curved end or offset portion for restoration of the diverter to operating position when the fiow of air past said portion exceeds a predetermined minimum. A still further object is the provisionof a combination diverter and air valve for a pneumatic system which is economical to construct, simple to adjust, and positive and accurate in operaion.

Other objects and advantages will be apparent from the following specification in which a preferred embodiment of the invention has been described for purposes of illustration.

In general, the above objects are accomplished by mounting the diverter in an opening in one wall of the material supply chute connecting a supply hopper with the intake end of a pneumatic suction conveyer. The diverter is mounted for movement between two positions, a first or operatin position, and a second or dumping position. The plate or diverter is rotatable between these two positions on a horizontal axis extendlng transversely of the above-mentioned openmg.

The diverter is so arranged and constructed that one end of it remains at all times substanitally outside the material supply chute, while the other end remains substantially inside the supply chute. The first or outer end is inclined upwardly from the axis in the operating position of the plate and is inclined downwardly r and outwardly from the aXis in the dumping position. The second or inner end of the plate extends downwardly from the axis and inwardly of the chute in the operating position of the plate and projects upwardly from the axis and across the major inner area of the chute in the dumping position of the plate in order to intercept the stock and divert it out through the opening. The first or outer end of the diverter plate is substantially heavier than the inner end in order that the weight of the parts will normally urge the plate to its dumping position. By adjustment of the location of the axis of rotation of the plate and by adjustment of the area of the second end of the plate which projects inwardly of the chute, it is possible to set the device for accurate operation so that the normal flow of stock and air from the supply hopper will maintain the plate in operating position, while a decrease in such flow below a definite predetermined minimum will permit the plate to shift to its dumping position and divert the stock until such time as the minimum desired rate of air flow is restored.

In the drawings accompanying this application, wherein like reference characters indicate like parts,

Figure l is a side elevation with certain portions broken away for clearness, showing the general location and arrangement of one embodiment of the invention.

Fig. 2 is a view similar to Fig. 1 showing additional portions of the supply hopper and conveyer, with the diverter in its dumping position.

Fig. 3 is a view similar to Fig. 1 showing one method of adjustment of the diverter plate.

Fig. 4 is a partial perspective view looking into the pneumatic system through the diverter plate opening, showing details of the diverter plate and of the auxiliary air inlet provided above the plate.

Fig. 5 is a view similar to Figs. '1 and 3, showing another method of adjustment of the diverter.

Fig. 6 is a perspective view of the-diverter pl-ate of the previous figures.

Fig. 7 is a sectional View on the line l-l of Fig. 3 showing details of the supporting means for the diverter, and v Fig. 8 is a partial sectional view on the line li- -8 of Fig. 5 showing details of one of the means limiting rotation of the plate.

As shown in Figs. 1 and 2, the present invention is designed for use in combination with a pneumatic system in which a supply hopper i0 feeds the desired material or stock to the intake 12 of the suction leg of a ieumatic conveyer 1-4. The hopper I0 is designed to supply both the stock to be conveyed and also a certain proportion of the air or gas which serves as the conveying medium.

Between the supply hopper Ill and the pneumatic "suction leg intake 12 is an enclosed stock supply chute l6 having one wall l8 provided with anopening defined by spaced upper and lower edges 22 and 24, respectively.

In the preferred form of the invention, the pneumatic conveyer intake I2 is both downwardly and laterally offset from the supply hopper l6, and the supply chute i6 is accordingly inclined to carry the material from one point tothe other.

In this case, as illustrated, the supply chute l6 has an inclined lower wall 18, and it is in this inclined lower wall I3 that the opening 29 i'sprovided. Thus the plane of the opening 20 is an- -gularly inclined at the lower portion of the supply chute [6.

Around the opening 20 isa, frame member "designated generally at 26. This frame member has a depending lower extension 28 on which a hinge 30 is mounted. Connected to the hinge 30 is a similar depending extension s2 on a frame member 34 which corresponds-in size and shape substantially to the frame member 2-6. Formed integrally with frame member-34 an-outwardly flaring air intake member 36. A gasket 38 between the frame members-26 and 34 forms an air tight joint between the air inlet or bell 36 and the frame member defining the opening 20. suitable clamping member 39 (Fig. 1) holds the parts in the position shown inthe drawings with gasket 38 clamped firmly between the frame members 26 and 34.

According to one preferred embodiment of the presentinvention, the opening 20 is so located and arranged that a portion of it lies vertically below the hopper 1-0. Such a portion or area is illustrated in-Fig. 2 between the vertioaldotted lines 40 and 42. It will be apparent that within this are'a,-stock may fall freely downwardly from the hopper I 0 and through opening 20, whenever the air flow through the supply chute rs and cenveyer 14 is cut off. Furthermore, it will be noted that-even th'o'ughthe lower wall 18 of ch'u'te I 6 is inclined downwardly and to the left in Fig. 2, the opening 20 extends all tlfe "way down I when no suction is being applied to the conveyor leg.

According to the present invention, an automatic diverter or valve member 44 is mounted in the opening 20. The diverter 44 is mounted for rotation en a horizontal shaft 46 having its axis extending transversely of the opening 20. Details of the means for supporting the plate 44 are particularly shown in Figs. 6 and '7. Thus the diverter plate 44 is provided with dependingbear-ing portions 48 and 50 which are located at each side of the plate at an intermediate point between the ends of the plate. These bearing portions 48 and 50 are provided with openings 52 which are aligned with each other and are designed to engage the shaft 46 and permit free rotation of the plate 44 on the shaft. For convenience the bearing portions 48 and 50 are provided as integral depending extensions on a transverse member 54 which is riveted or otherwise fastened to the diverter plate 44 as shown at 56.

The shaft 46 is provided with reduced threaded extensions 58 and 60 at its respectiveends. These threaded extensions are engaged in slots 62 (Figs. 1, 2, 3, and 5) in the side walls of the air intake member 36. Washers 64 and lock nuts 66 engage the threaded extensions 58 and 60 and clamp the shaft 46 rigidly in its desired adjusted position along the length of slots 62.

As shown in Fig. 2, the slot "62 is substantially in the plane of opening 20 by virtue of the fact that it is parallel to the plane of frame 26 and spaced slightly outwardly therefrom. It should also be noted from this figure that slot 62 extends across the area of the opening between the vertical dotted lines 40 and '42 and projects upwardly to the right in Fig. 2 beyond said area and also downwardly to the left in said figure beyond said area. Thus the slot 62 extends far enough so that the shaft 46 which defines the axis of rotation of the diverter plate '44, can be shifted laterally, i. e., inwardly or outwardly of the chute so that the axis of rotation of the plate can be adjusted with respect to the path of free fall of the stock discharged from supply hopper In -'other words, with the shaft located in the upper or outer portion of the slot as shown in Fig. 2, the area represented by the vertical .pro- 'jections 49 and 42 would lie inwardly of the axis of rotation of the plate. On the other hand, if the shaft 46 were adjusted to the lower or inner end of the slot 62, then the area defin'edby the dotted lines 40 and 42 would lie outwardly 'or to the right of the plate pivot. As described below, this particular arrangement of the adjusting-slot 62 makes it possible to vary the point at whichfreely falling stock strikes diverter .plate 44 when the suction in the conveyer tube 14 is cut off. By such adjustment it is possible to pre- 'cletermin'e the conditions under which'the diverter plate 44 will move from operating to dumping position and vice versa.

As shown 'in Fig. 6, the diverter plate 44 has oppositely extending ends 58 and H3 which are arbitrarily designated as the first end -68 and "the second end 16 for convenience in the following discussion. These first and second ends of the plate 44 extend in substantially opposite directions from the axis of the bearing openings 52.

That portion of the diverter plate 44 between the axis of bearing openings 52 and the first end 68 is substantially fiat as indicated at 12. This fiat section includes integral upwardly extending sidewalls i4 which thus provide a substantially rigid channel-shaped section extending from the pivotal axis to the first end 68.

The side walls 14 which cooperate with the flat plate portion 72 at the first end of the diverter 44 not only provide a substantially rigid channelshaped section at this point, but also serve two additional important functions. First of all, the upper edges of these side walls i4 provide means for limiting the rotation of the first end. 68 of diverter plate 44 in an upward direction. Thus the upper edges of side walls 74 will engage the upper wall portions TB of the air intake member 36 to limit upward rotation of this outer end of the diverter plate. Since this upper wall portion 16 of the air intake member 36 efiectively defines the same general area as the upper edge 22 of opening 20, it may be said that the upward rotation of the first end of the diverter plate is substantially limited by engagement of the side walls at this end of the plate against the upper edge of the air intake opening.

As shown in Fig. 4, the use of these side walls .14 as stop means to engage the upper wall 16 of the air intake section 3-6 serves to space the base portion E2 of the plate a predetermined distance below the upper edge of the opening. auxiliary air intake opening is provided at 18 bounded by the side walls 14, the bottom plate 12 of the first end of the diverter, and the upper wall portion '16 of the air intake bell.

It should also be noted from Fig. 4 that in this upper limiting position of the first end of the diverter plate, which may be regarded as the operating or first position of the plate, the second or opposite end of the plate extends downwardly from the axis of shaft 46 and inwardly I of the material supply chute It at a point spaced above the lower edge 24 of opening 26. Thus a further auxiliary air intake opening is provided through the area 80 between the lower edge 24 of opening and the end 10 of the diverter plate.

Thus in the operating position of the diverter plate 44, as illustrated in Fig. 1, with suction applied at a remote portion of the conveyer tube 14, air will be supplied to the suction leg of the conveyer through three sources. These sources are designated generally by the arrows A-l, A-2, and A-3 in Fig. 1 which represent respectively the air supply coming from the hopper Iii, the auxiliary air received through the area below the diverter plate 44, and the further auxiliary air supply which passes in through the open area 18 above the diverter plate at the upper portion of opening 20.

The second or outer end 10 of diverter 44 includes an outer portion or area 82 which is substantially parallel to the plane of portion I2 at the first end of the plate, but which is downwardly offset from said plane. Between this downwardly ofiset section 82 and the fiat portion 12 adjacent the pivotal axis of the plate, there is a smooth reversely curved section defined by the downwardly curved portion 84 immediately adjacent the axis of rotation of the plate and the outwardly or reversely curved section 85 which joins the Thus an i 6. downwardly curved portion 84 to the downwardly offset section 82. This S-shaped or reversely curved section at 84 and 86 includes no side wall portions and the degree of curvature of the parts and the extent of downward ofiset of the portion 82 may accordingly be adjusted readily by mere bending of the plate. The curvature of portions 82, 84, and i2 is preferably such as to give an airfoil eiTect, so that the air passing beneath the plate at A-2 will be diverted downwardly and will create an area of reduced pressure or partial vacuum beneath the plate. This suction will tend to restore the plate to the operating position of Fig. 1, whenever the volume rate of air flow at A-2 exceeds a predetermined minimum.

An essential feature of the present invention is the construction of diverter plate 44 in such a manner that its first or outer end which'comprises the channel-shaped section with base portion l2 and side walls 14 is heavier than the second or inwardly projecting end represented by the downwardly offset section 82 and the smoothly curved intermediate portions 84 and B6. In one preferred embodiment of the invention, the total weight of the diverter plate was 14 ounces, of which the first end or tail 68 weighed 10.5 ounces, while the inner or second end portion weighed only 3.5 ounces. Thus in this case, the weight of the first or outer end of the plate was three times as great as the weight of the inner or second end thereof.

This difference in weight between the two ends of the plate will accordingly urge the first end 68 of the plate downwardly at all times and will tend to rotate the plate 44 in a clockwise direction as viewed in Figs. 1 and 2 from the operating position of Fig. 1 tothe second or dumping position shown in Fig. 2. In order to limit the downward rotation of the first end of the plate a stop member is provided. In this case the stop member is shown in the form of a screw 88 projecting inwardly through the side wall of the enclosed supply chute l6 and projecting into the path of upward movement of the inner portion 82 of the second end 70 of the diverter plate. Thus the greater weight of the first end of the plate will at all times urge the diverter plate from the position of Fig. 1 toward the position of Fig. 2, the limit of movement in this direction being determined by engagement of the plate against the stop 88. The head of the screw or stop 88 is shown at 90 on the outside of the wall of chute [6 (Fig. 8).

With the foregoing details of construction of the preferred embodiment of the present invention in mind, the operation and function of the parts will now be described.

When suction is applied to the pneumatic conveyer leg l4 and when the conditions are such that a normal predetermined volume rate of flow of air enters the intake l2 of the suction leg from the three sources represented by arrows A-l, A-2, and A-3, the diverter plate 44 will be maintained in the operating position of'Fig. 1. The tendency of the diverter plate to rotate to the position of Fig. 2 by reason of the greater weight of the first end of the plate 'will'be more than offset by the flow of air and stock from the hopper against the inwardly and downwardly pro- Jecting portion 82 of the second end of the plate. The fiow of stock in this case is designated schematically by the arrow S in Fig." 1. Since the stock will be substantially entrained in a; large volume of air, the actual force exerted-by the stock will be small in comparison to the force EMQSBQ.

75 resultingrfrormthaair flow against-the. projectin areaz82 of the diverterplatep.

It: is; also: possible that; the downwardly offset construction of. theiportion 9,2 and particularly; the curved sections: 84'. and 8E, disturb; the new of -ai'r inwardly along: the generalz path indicatedby'thearrow A -Z" inv such-a mannert'hat an. air-. foil efi'ect-is obtained'whichicreatesa slight vacuum beneath the area- 1?; andyor cunved portion 86} and thusalso tends. to rotate the diverter: plate counterclockwise the figure, i;. e., in a direction opposite to that in which theweight of-"the end 68 would tend to rotate the plate. 011' the other hand, the air at A-2- striking the second end of the diverterwould;- tendto rotate theplate clockwise in the samemanner as the excess weight of the first end if the shape of saidisecond end or the volume rate ofairflow were such that no airfoil or suction effect isobtained'. Itis believed that the actual resulting efiect of air- A-Z' willthus depend ontheshape and area of the plate and the rate of air flow past it Whichever Way the air A:-2 tends to rotate. the plate inany given case; it is believedto be possible to. balance and adjust the various forces and'factorsso that the desired operation willbe achieved; by following the principles and teachings. set. forth, herein.

The flow-of air through the'remaining auxiliary opening as indicated by the arrow'A-3. will also assistirnmaintaining theplate in the operating positiomof Fig. I andv in addition will serve to maintain the-channel-shaped section .of thefirst endfof theplate clear. of any particlesjof material which may previously have droppedv thereon; The angle. of inclination. of the channel in the operating position OfFig. 1, may be less than the angle of. repose. of the stock which is deposited thereon. Bhus the air at A-Bcarries such stock in to. the suction. leg and. makes the. diverter plate. self-cleaning.

V Accordingtothe present invention,.the-normal volume rate of flow. of air. through the sources A-el, A.-Z:;, and A.3, the impact of the-stock as indicated. by. arrow S, and. the effect of the weighted; endofthe. plate. 5.4. will be so balanced thatthediverter plate will remain in the operating, position of Fig. 1. as. long; as-the volume rate of. air flow. remains. above. a predetermined minimum. For. convenience in illustration, this condition maybe illustrated qualitatively by, a rough equation as follows:

('IEhis. equation assumesithat the. air. at As has no airfoil or suction efiect butlmerely acts. clockwise in. Fig. 1. In case; the net effect of air at A2 is in, the opposite, or counterclockwisedirection, them the: factor would appear on the-left side: of.- the. expression, instead of. the right side; a V

In theahove equation; A1- and. A2 represent the forces due tothe air flow, W represents. the excess weight. off. the. first: end or. the plate: 44; and. S ..repr.esents. theforce of the. 51 061;; engaging the second. end-ofthe plate; 11, Z2, 15,, and lw represent thadistances. on lever arms: from. the axis. of. shaft. 55. at whichuthe various forces A1, ,S. and W are. effective. As long as the elementsv on the left side of the equation exceed those on the; right in. total effect, it is obvious that; the. diverter. plate; will remain in the. operatingrpositionofEig; l.- If; new the-normal supply of-i air tothe pneumati'c: conveycr leg; [14; is reduced, below. 911 1 37 determined; minimum, the forces represented. at A1v and; will both. be; decreased; Sinca; however, the main flow of air comes from the supply; hopper. as designatedl by force A1,. this; force will decrease much more; rapidly than: the force A; andawill in. fact; dropasubstantially. toizero since thelo'wer' portion of opening Eileen; handle sub. stan'ti'ally; all of-thel. air required when. the: con-'1 vey-en is partially choked. li'hus the condition of balance in the above expression will be ree versed andimay be represented as:,follo.wsz

In this'connection; as soon astheair flow represented at A1 is substantially decreased; the stock represented by. theforce'S: will tend to drop more nearly vertically as shown by the vertical positionof arrow S in Fig; 2. Thus the effective centerofimpact of the-stock againstthe diver-ter plate will. move somewhat to the right in; the figure, Le. nearer! the: axisof shaft 46-m Fig. 25; The efiective: lever arm Is is thus also reduced and this likewise contributes to the. reversal of balance in the equation. In other words, the excess weight of the first end or tail. of the; divert'er plate will be suihcient', when the air flow is-reduced-below the'predetermined minimum, to tilt theplate' automatically from the operating position of Fig. 1 to the dumping position of Fig. 2 without any attention on thepart offthe operator. Since the end 10': of the; diverterplate extends upwardly across the major areaof" the supply chute 15, the diverter platewill intercept substantiallyall of the stocli dropping from-the hopper H3 and'will divert it outwardly' through the opening 2Bso that-no additional stock is received at the intake [2c of the suctionleg-until thechoked condition is relievedand the air supply returns to normal. The sides 14* of the channel section form a spout-to assist inguiding the diverted material;

As soon as thevolume rate ofair flow again increases above the predetermined minimum; there will be a tendency to-draw air again from the supply hopper l9- and thus the force representedby arrow' A -l will be restored; and the diverterplat'ei will automatically shift back from the dumping position or Fig. 2-- to the operating position of Fig. l andwill remain in. the latter position until the air flow again drops below the predetermined minimum; Theresetting; action of? the diverter may *be' assisted" by the air-foil or suction eifeet, ifany; on the second end of the plate.

As previously described; it is possible to adjust the point a-twhich the diverter' plate will function inany one of severaldifi'erenti Ways. Thus adjustment-of the shaft l eoutwardly and inwardly along the'slots- 62 will change both the point at which-freely falling stock will-strike-the plate when'the latter isin its dumping position as shown-in-Fig'. 2 and-also will'changetl ieefiective area of the second end of the plate which projects into the path-of the air and stock; as illustrated-by the-dotted and heavy line positions or Fig: 5-.- Similarly, as illustrated ill-Fig. 3, the bending of; the curved inn'er or se'condend of the diverter'plate serves as a means for adjustment of the area of the plate which-projects into the material supply: chute; without any "changein the location. of the axis of pivot shaft 46. Such-bench ing a-lso changes the curvature of the plate end and can thus alter th'e possibleairflow orsuction eifecta on the undersurface of the plate;

- .It has been found in actual operation that the heavier the stock to be received from supply hopper ID, the farthest downwardly the shaft 46 should be adjusted in slots 62. For extremely light stocks the shaft 46 can remain at the upper end of the slot as shown in Fig. 2.

While certain theories have been advanced to explain the operation of this improved diverter plate, the fact remains that a diverter constructed in accordance with the foregoing details accomplishes the objects set forth at the beginning of this specification and functions automatically to divert the stock from the supply hopper away from the suction leg intake whenever the volume rate of air flow within the pneumatic conveyer drops a predetermined minimum.

The diverter plate also functions completely automatically to restore itself to normal or operating position and again feed the stock from the hopper toward the intake of the pneumatic conveyer whenever the volume rate of air fiow in the suction leg exceeds the predetermined minimum. As a result, the diverter plate of the present invention in the combination shown and claimed herein, completely eliminates the conditions of complete choking which often occur in pneumatic systems in the absence of such a device. More important, the automatic resetting of the device limits the amount of stock diverted to the bare minimum necessary to permit the pneumatic conveyer section M to clear itself of partial chokes. Finally a plurality of adjustments are provided to make it possible to set the diverter for accurate predetermined operation at any desired point Withina wide range of operating conditions.

Since minor variations and changes in the exact details of construction will be apparent to persons skilled in this field, it is intended that this invention shall cover all such changes and modifications as fall within the spirit and scope of the attached claims.

We claim:

. 1. A combination material supply diverter and air inlet valve for a pneumatic conveyer having a supply hopper through which air and stock are fed, and a suction leg intake located below and laterally offset from the hopper, which comprises an enclosed material supply chute connecting the hopper and intake and having a lower wall inclined downwardly from the hopper to the intake, said wall having an air inlet opening defined by upper and lower edges, and a diverter plate mounted in the opening for rotation on a horizontal axis extending transversely of the opening betweena first or operating position in which the plate is inclined with a first end of the plate extending upwardly and outwardly of the chute from said axis and a second end extending downwardly and inwardly of the chute from the axis and a second or dumping position in which the plate is oppositely inclined, with said first end extending downwardly and outwardly from the axis and said second end projecting upwardly and inwardly from the axis, said first end of the plate being heavier than said second end to urge the plate from first to second position at all times.

2. A combination diverter and air valve according to claim 1 havin means spacing the first end of the plate from the upper edge of the opening when the plate is in operating position and thereby providing an auxiliary air inlet above the plate.

3. A combination diverter and valve according to claim 2 in which said spacing means comprises vertically projecting edges on the sides of the first end of the plate, said edges forming with the plate a channel shaped section for guiding the stock away from the suction leg intake when the plate is in its second position.

4. A combination material supply diverter and air inlet valve for a pneumatic conveyer having a supply hopper through which air and stock are fed, and a suction leg intake located below and laterally offset from the hopper, which comprises an enclosed material supply chute connecting the hopper and intake and having a lower wall inclined downwardly from the hopper to the intake, said wall having an air inlet opening defined by upper and lower edges, and a diverter plate mounted in the opening for rotation on a horizontal axis extending transversely of the opening between a first or operating position in which the plate is inclined with a first end of the plate extending upwardly and outwardly of the chute from said axis and a second end extendingdownwardly and inwardly of the chute from the axis,

and a second or dumping position in which the.

plate is oppositely inclined, with said first end extending downwardly and outwardly from the axis and said second end projecting upwardly and inwardly from the axis, said first end of the plate being heavier than said second end to urge the plate from first to second position at all times, and said second end of the plate having a portion projecting into the chute in the normal path of air and stock coming from the hopper and urging the plate from second to first position in response to normal air and stock flow toward the suction leg intake.

5. A combination diverter and valve according to claim 4 in which the projecting portion of the second end of the plate is downwardly oifset from the plane of the first end of the plate.

6. A combination diverter and valve according to claim 5 in which said downwardly offset projecting portion is joined to the remainder of the plate by a smooth reversely curved section.

7. A diverter plate for the air, and material supply chute of a pneumatic conveyer system comprising laterally spaced bearing portions located at an intermediate portion of the plate for rotation of the plate on a transverse axis, the plate having integral upwardly extending sides forming a rigid channel section extending substantially from the axis of the bearing portions to one end of the plate, and the other end of the plate being curved downwardly and then outwardly from the axis thereby providing an outer portion at said other end which is downwardly offset from the plane of the bottom of said channel section.

8. A diverter plate according to claim '7 in which the center of gravity of the plate is on the same side of the bearing portions as the channel section end.

9. A diverter plate for the air and material supply chute of a pneumatic conveyer system comprising laterally spaced bearing portions located at an intermediate portion of the plate for rotation of the plate on a transverse axis, the plate having a first portion extending from said axis to one end of the plate in substantially a fiat plane, and a second portion extending from said aXis to the other end of the plate, at least part of the second portion being oiTset from said first portion in a direction perpendicular to said plane.

10. A diverter plate according to claim 9 in which the outer end of said second portion is offset from said first portion in a direction perl1 pendicular to said plane and is joined to the remainder of the. plate by a smooth reversely curved section.

11. A diverter plate for the air and material supply chute of a pneumatic conveyer system comprising a fiat plate-like body portion extending in a given plane. and adapted to lie, parallel to and immediately adjacent an air flow path in said system when the plate is in a first position,. bearing means on the plate adapted to support the plate for movement of said flat body portion between said first position and a second position in which the fiat body portion extends away from said path, and means on the plate automatically restoring the plate from said sec- 1 nd. to said first position in response to a predetermined rate of flow along said path, said restoring means including an, airfoil-like curved portion on the plate having a convex surface offset from the planev of said flat body portion ina direction perpendicular to said plane and toward said airv flow path, thereby forming a low pressure area along said convex surface to provide the necessary restoring force in response to said predeterminedrate of fi-ow along the path.

12. An automatic diverter for a pneumatic conveyer having a supply hopper through which air and stock are fed, and a pneumatic suction leg intake below the hopper; which comprises an enclosed stock supply chute connecting the hopper and intake and having a wall provided with an opening defined by top and bottom edges, and a diverter plate mounted in the opening for free rotation on a horizontal axis extending transversely of the opening, said plate having first and second end portions extending in substantially opposite directions from said, axis, means limiting upward rotation of the first end of the plate at an operating position in which the first end portion extends upwardlyfrom said axis across the upper portion of the opening, means limiting, downward rotation of the first end of the plate at a dumping position in which said, first end portion extends downwardly and outwardly from the axisand chute, said first end portion being movable between said operating and dumping positions through a minor arc substantially completely outside the, chute, and the second end portion, of the plate projecting inwardly. and downwardly from the axis across the lower part of said opening inthe operating position of the plate and projecting, inwardly and upwardly from the axis and. across the major area of the chute in said dumping position, the first end of the plate being heavier than the second end and thereby urging the plate ,to dumping'position, and the second end having an area engaged'by air and stock flowing from the hopper tothe suction leg intake andthereby moving the plate to operating position against the weight of said first end, whenever a normal predetermined volume rate of air is being drawn to the intake through the chute. v

13. An automatic diverter according to claim 12 having adjustable means supporting the diverter for vertical adjustment of said axis at different levels in said opening.

14. An automatic diverter according. to claim 12 having means spacing the first end of the plate from the upper edge of the opening when 12 the plate is in operating position and thereby providing an auxiliary air inlet above the plate 15. An automatic diverter for a pneumatic conveyerhaving a supply hopperthrough which air and stock are fed, and a suction leg intake located below and-laterally offset from the hop per, which comprises an enclosed material supply chute connecting the hopper and intakeand having a lower wall inclined downwardly from the hopper to the intake, saidwall having anair inlet opening defined by upper and lowen edges, with a substantial area of the opening being located vertically below the hopper, whereby in the absence of. air flow through the hopper and supply chute a portion of the stock leaving the hopper can fall freely and directly through the opening; a diverter plate; and" means mounting the plate in the opening for free rotation on a horizontal axis extending transversely of the opening, said plate having first and second end portions extending in substantially opposite directions from said axis; means limiting upward rotation of the first end of the plate at anoperating position in which the first end portion extends upwardly from said axis across the upper portion of the opening, means limiting downward rotation of the first end of the Plate at a dumping position in which said first end portion extends downwardly and outwardly'from theaxis and chute, said first end portionbeing movable between said operating and dumping positions through a minor arc substantially completely outside the chute, and the second end portion of the plate projecting inwardly and downwardly from the'axi-s across the lower partof said opening in the operating position of the" plate and projecting inwardly and upwardly from the axis and across the major" area of the chute in said dumping position, the first end of-the'platebeing heavierthan the second end and" thereby urging the plate to dumping position, and the second end having an area engaged by airand stock flowing from the hopper to the suction leg intake and thereby moving the-plate cooperating position against the weight of said first end; whenever a normal predetermined volume rate of air is being drawn to the intake through the chute.

16; An automatic diverter according to claim 15 in which the mounting means forthe plate is adjustable to shift said axis inwardly oroutwardly of the chute with respect to the'portion of" the opening vertically below the hopper, thereby varying the effective center of -impactof the freely falling stock against the'plate to predetermine the volume rate of air flow required to move the plate from dumping to operating position. 7

DONALD E. SCHA'ETZEL. RANDALL J. CHILDRESS;

References Cited in theifile of this patent- UNITED STATES PATENTS Number Name Date 620,85 l Schuman Mar. '7, 1899 636,372 Williamson Nov. '7, 1899 1,498,776 Bernert June 24, 1924 FOREIGN PATENTS Number Country Date 325,615 Germany Sept. 16, 1920 

